On a number of occasions, DailyTech has discussed a concern
that appears to be growing among advocates for blind
pedestrians. With the rise of hybrid vehicles which run nearly
silent at low speeds and fully-electric vehicles, many blind
pedestrians are concerned that they won't be able to listen for
typical audible cues present in modern internal combustion engines.

The NHTSA is already
working on guidelines that would require hybrids and electric
vehicles to produce sounds that can be heard by pedestrians at low
speeds. However, Nissan it taking matters into its own hands with the
upcoming Leaf electric vehicle.

The Nissan Leaf will use a sine-wave
sound system that will "whistle" while the vehicle is
traveling at less than 19 mph. According
to Just-Auto, the sound system will sweep from 2.5kHz to
600Hz.

In addition to the artificial sound
while driving at low speeds, the vehicle will also make intermittent
sounds when put into reverse to alert people. And in a nod to
traditional gasoline and diesel-powered vehicles, the Leaf will make
a louder sound when first started up to alert pedestrians to the
vehicle's presence.